Rollover protection systems of this kind serve the protection of occupants of motor vehicles without protective roofs, typically of convertibles or sports cars.
In methods known to the art a fixed roll bar spanning the entire vehicle width is provided or a fixed roll bar without height adjustment is allocated to each vehicle seat.
In both solutions, the increased air resistance and the generation of driving noises are felt to be disadvantages, aside from the impairment of the vehicle appearance.
Therefore, the design solutions increasingly prevailing in the market provide a roll bar which is normally retracted and quickly extended into a protective position in the case of danger, i.e. when a rollover threatens, in order to prevent the occupants of the vehicle from being crushed by the overturning vehicle.
Typically, these solutions provide a rollover structure mounted in a guide structure firmly attached to the vehicle, wherein the rollover structure is U-shaped or formed from a profile structure, and wherein the guide structure is attached inside a cassette-type housing. This rollover structure is normally kept in a lower resting position by a holding device working against an actuating compression spring, and in the case of a rollover, can under sensor control be brought into an upper, protective position by the force of the spring while the holding mechanism is released and while an interlocking device preventing the roll bar from being pressed down is activated.
For this purpose, one cassette is allocated to each vehicle seat.
The holding device typically is equipped with a holding element which is attached to the rollover structure and connected to a tripping element of a sensor-controlled tripping system by a disengageable mechanical activation mechanism, wherein the tripping element is typically formed by a tripping magnet, the so-called crash magnet, or by a pyrotechnical tripping element.
The interlocking device typically comprises a pivoting articulated, spring-preloaded latch with toothed segments and a fixed tooth rail, a latch pin or similar device, wherein one interlocking element is connected to the roll bar, while the other is firmly connected to the vehicle.
A cassette design of this kind of a rollover protection system with a U-shaped roll bar is disclosed, for example, by the patent application DE 43 42 400 A I.
The known rollover system according to the patent application DE 43 42 400 A I has a housing in the form of a U-shaped cassette with one open side and with two lateral walls each of which is equipped on the open side of the cassette with a chamfered angled piece for firmly fastening the cassette to the vehicle, to each of which, in addition, a bottom plate is attached, and which, finally, are linked to one another in front via a cover wall. Furthermore, the rollover protection system is equipped with a U-shaped roll bar comprising a curved segment and two parallel leg pipes each of which has a closed circumferential surface and which are connected at their open end via a cross arm-like, stiffening fastening element.
Furthermore, the system is equipped with two standpipes each of which is with one end attached to the housing bottom, each of which in its interior contains one compression spring solely for actuating the roll bar, and each of which is enveloped coaxially by a leg pipe and also has a closed circumferential surface as well as a guide block attached flatly at the upper end of the housing to the lateral walls of the cassette and equipped with guide openings to allow additional external guidance of the leg pipes.
An improved version of a cassette system of this kind disclosed by the patent application DE 100 40 649 C1 is equipped with U-shaped lateral parts within which the guide block is attached with the aid of U-shaped extensions and the cross arm with the corresponding extensions is mounted.
According to prior art, the mechanical connection of the guide block to the U-shaped lateral parts is provided by means of eight riveted joints. Riveted joints typically cause protrusions enlarging the assembly dimensions of the cassette beyond the width of the U-shaped lateral parts. Since the assembly dimensions, as set by the vehicle manufacturer, are tending toward a decrease of the measurements, it became necessary to countersink the rivet holes in a manufacturing step preceding the riveting procedure so that the rivet head will not protrude. This procedure, however, is relatively costly.
The invention relates to the object of creating a mechanical connection of the guide block to the U-shaped lateral parts which can be produced with relatively simple means and without protrusions for the rollover protection system referenced above for motor vehicles with a roll bar mounted in a cassette-type housing which can be firmly attached to the vehicle and which is equipped with two U-shaped lateral parts which are, without lateral protrusion, linked to one another by a bottom part at the bottom, and by a guide block at the top.
This object is achieved according to the invention by the fact that the guide block and the U-shaped lateral parts are equipped with integrated fastening elements providing a form-fit connection in the form of a latch-type or clip-type connection.
A form-fit connection of this kind without lateral protrusion, which thus is directed into the interior of the cassette, is relatively easy to manufacture, in particular, by constructing and shaping the fastening elements already during manufacture of the U-shaped lateral parts and the guide block. The joining procedure advantageously does not require tools and, in particular, no riveting station. In addition, a very assembly-friendly form-fit connection results, since the guide block can simply be inserted into the U-shaped lateral parts and then automatically latches into the desired position.
A series of possibilities for the construction of a latch-type or clip-type connection of this kind are available to the expert. According to a refinement of the invention, an advantageous design provides an elastically yielding strap or pin, bent toward the interior of the cassette, to serve as fastening element on each of the two legs of the U-shaped lateral parts, and provides lateral grooves as the corresponding fastening elements at the ends of the guide block, mounted in the U-shaped lateral parts, in such a way that in the desired fastening position, the strap or pin latches into the respective groove.
A form-fit connection of this kind can advantageously be produced economically by relatively simple means by providing a strap or pin cut free and stamped from the material of the U-shaped lateral parts and/or by generating the groove by milling it out of the guide block.